1. Field of the Invention
The present invention relates to a motor vehicle seat with an adjustable reclining backrest in accordance with the superordinate concept of claim 1.
2. Description of Related Art
In motor vehicle seats with manual tilt adjustment of the backrest the connecting element of the two tilt adjustment fittings are configured as hollow sections with a relatively small radial dimension in order to economize on weight. In comparison to electrical motor drives, this is possible, because the connecting element must transmit a relatively low torque from one to the other tilt adjusting fitting. In electrical motor driven connecting elements these are configured as solid sections according to the prior art.
In order to assure that the connecting element does not “wander out” of the tilt adjusting fitting or is not propelled out in the event of a side impact, it is necessary to affix the connecting element axially on the seat; in other words, to secure it. In manually adjustable backrests the connecting element configured as a hollow section according to the prior art (see, for example, DE 32 29 107 C2) is affixed to the outside of the tilt adjusting fitting. Clip washers, cups, screws or nuts are used as securing elements, for example. This type of axial fixation is associated with significant drawbacks, because the width of the backrest frame has tolerances in millimeters due to manufacturing considerations and due to cost considerations the connecting elements cannot be individually matched to each backrest frame but are pre-fabricated parts. In relatively over-long connecting elements a very annoying rattling noise occurs during movement, because the connecting element has a relatively large, axial play and accordingly can move back and forth. In contrast, with relatively extremely short connecting elements the base of the backrest frame is jammed or wedged in. Obviously, this does not result in a rattling noise but in difficulty moving the tilt adjusting fitting.
These drawbacks are eliminated by a solution disclosed in DE 33 25 045 C2. According to this prior art the connecting element has an expansion abutting on the inner side of one of the tilt adjusting fitting, while on an outer side a manual wheel is arranged for operating the connecting element. The connecting element is thereby secured against axial displacement to one of the tilt adjusting fittings, while it is mounted axially freely displaceable in the other tilt adjusting fitting. In this fashion mounting without rattling or jamming of the connecting element is possible. Nevertheless, using this solution folding back or opening of the tilt adjusting fitting not engaged on both sides cannot be ruled out.
The object of the present invention is to provide a motor vehicle seat of the aforementioned type, which combines the advantages of the prior art; that is, one that prevents folding back or opening of the a tilt adjusting fitting and at the same time allows easy assembly of the connecting element without rattling and axial jamming.
Said object is achieved by the invention by means of a motor vehicle seat with an adjustable reclining backrest according to the present invention.